Light: wavelength, frequency and energy

Answer Key - Grade 10 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Using E = hc ÷ λ with h = 6.626 × 10⁻³⁴ J·s and c = 3.00 × 10⁸ m/s, what energy does a 400 nm photon carry, in units of 10⁻¹⁹ J, Ari?

   4.97 × 10⁻¹⁹ J
2. 2.

   Using E = hc ÷ λ with h = 6.626 × 10⁻³⁴ J·s and c = 3.00 × 10⁸ m/s, what energy does a 656 nm photon carry, in units of 10⁻¹⁹ J, Bo?

   3.03 × 10⁻¹⁹ J
3. 3.

   Using E = hc ÷ λ with h = 6.626 × 10⁻³⁴ J·s and c = 3.00 × 10⁸ m/s, what energy does a 250 nm photon carry, in units of 10⁻¹⁹ J, Esme?

   7.95 × 10⁻¹⁹ J
4. 4.

   By E = hc ÷ λ, what happens to photon energy as wavelength shrinks, Kira?

   • It shrinks
   • It stays the same
   • It grows
5. 5.

   One photon's frequency is three times another's. How do their energies compare, Luz?

   • Three times as much energy
   • One third as much energy
   • Nine times as much energy, by squaring
6. 6.

   Milo says radio waves carry more energy per photon because their waves are bigger. Agree or disagree?

   • Agree: radio travels farther
   • Disagree: longer waves, less energy
   • Agree: bigger waves are much stronger
7. 7.

   Noah says red photons carry more energy than blue ones because red looks warm. Agree or disagree?

   • Disagree: blue has more per photon
   • Agree: longer waves hold more energy
   • Agree: warm colors carry more
8. 8.

   Pia says blue light travels faster than red light in a vacuum. Agree or disagree?

   • Disagree: all colors travel at c
   • Agree: more energy, more speed
   • Agree: blue waves are quicker
9. 9.

   Why do ultraviolet photons cause sunburn when visible light doesn't, Tala?

   • UV is a kind of heat
   • Each UV photon has more energy
   • UV waves are longer
10. 10.

    Compared with visible light, how much energy does each microwave photon carry, Zee?

    • Much less
    • Exactly the same
    • Much more